U.S. patent number 9,548,463 [Application Number 14/587,394] was granted by the patent office on 2017-01-17 for organic photoelectronic device and image sensor.
This patent grant is currently assigned to Samsung Electronics Co., Ltd.. The grantee listed for this patent is Samsung Electronics Co., Ltd.. Invention is credited to Xavier Bulliard, Chul Joon Heo, Yong Wan Jin, Gae Hwang Lee, Kwang Hee Lee, Dong-Seok Leem, Kyung-bae Park, Rie Sakurai, Tadao Yagi, Sung Young Yun.
United States Patent |
9,548,463 |
Yagi , et al. |
January 17, 2017 |
Organic photoelectronic device and image sensor
Abstract
Example embodiments relate to an organic photoelectronic device
including a first electrode and a second electrode facing each
other, and an active layer between the first electrode and the
second electrode, wherein the active layer includes a first
compound represented by the following Chemical Formula 1, and an
image sensor including the organic photoelectronic device.
##STR00001##
Inventors: |
Yagi; Tadao (Hwaseong-si,
KR), Sakurai; Rie (Suwon-si, KR), Park;
Kyung-bae (Hwaseong-si, KR), Yun; Sung Young
(Suwon-si, KR), Lee; Gae Hwang (Seongnam-si,
KR), Lee; Kwang Hee (Yongin-si, KR), Leem;
Dong-Seok (Hwaseong-si, KR), Bulliard; Xavier
(Seongnam-si, KR), Heo; Chul Joon (Busan,
KR), Jin; Yong Wan (Seoul, KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
Samsung Electronics Co., Ltd. |
Suwon-si, Gyeonggi-do |
N/A |
KR |
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Assignee: |
Samsung Electronics Co., Ltd.
(Gyeonggi-do, KR)
|
Family
ID: |
55075311 |
Appl.
No.: |
14/587,394 |
Filed: |
December 31, 2014 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20160020415 A1 |
Jan 21, 2016 |
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Foreign Application Priority Data
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Jul 21, 2014 [KR] |
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10-2014-0092001 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
C07F
7/0834 (20130101); H01L 51/008 (20130101); H01L
51/0094 (20130101); H01L 51/4253 (20130101); H01L
51/0046 (20130101); H01L 2251/308 (20130101); H01L
51/442 (20130101); H01L 27/307 (20130101); H01L
27/301 (20130101) |
Current International
Class: |
H01L
51/00 (20060101); C07F 7/08 (20060101); H01L
27/30 (20060101); H01L 51/42 (20060101); H01L
51/44 (20060101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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2011-140639 |
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Jul 2011 |
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JP |
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5296674 |
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Sep 2013 |
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JP |
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WO-9424612 |
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Oct 1994 |
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WO |
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Other References
Graham E. Morse et al., "Phthalimido-boronsubphthalocyanines: New
Derivatives of; Boronsubphthalocyanine with Bipolar
Electrochemistry and; Functionality in OLEDs.", Applied Materials
& Interfaces, American Chemical Society, 2011, pp. 3538-3544.
cited by applicant .
Julia Guilleme et al., "Triflate-Subphthalocyanines: Versatile,
Reactive Intermediates for Axial Functionalization at the Boron
Atom", Aromatic Macrocycles, Wiley Online Library, 2011, pp.
3506-3509. cited by applicant .
Graham E. Morse et al., "Aluminum Chloride Activation of
Chloro-Boronsubphthalocyanine: a; Rapid and Flexible Method for
Axial Functionalization with an Expanded Set of Nucleophiles",
Inorganic Chemistry) ACS Publications, 2012, pp. 6460-6467. cited
by applicant .
Mabel V. Fulford et al., "Crystal Structures, Reaction Rates, and
Selected Physical Properties of Halo-Boronsubphthalocyanines (Halo
= Fluoride, Chloride, and Bromide)", Journal of Chemical
Engineering & Data, ACS Publications, 2012, pp. 2756-2765.
cited by applicant .
Jeremy D. Dang et al., A Boron Subphthalocyanine Polymer
Poly(4-rnethylstyrene)-copoly(;phenoxy boron subphthalocyanine),
ACS Publications, American Chemical Society, 2012, pp. 7791-7798.
cited by applicant .
Biwu Ma et al, "Solution processable boron subphthalocyanine
derivatives as active materials for organic photovoltaics", Organic
Photovoltaics X, Proc. of SPIE vol. 7416, pp. 1-6. cited by
applicant .
Satoshi Aihara et al., "Stacked Image SensorWith Green- and
Red-Sensitive; Organic Photoconductive Films Applying Zinc Oxide;
Thin-Film Transistors to a Signal Readout Circuit", IEEE
Transactions on Electron Devices, vol. 56, No. 11, Nov. 2009, pp.
2570-2576. cited by applicant .
Hokuto Seo et al., "Colo Sensors with Three Vertically Stacked
Organic Photodetectors", Japanese Journal of Applied Physics, vol.
46, No. 49, 2007, pp. L1240-L1242. cited by applicant .
CAS Registry, XP55232087, C:\\EPODATA\SEA\eplogf\EP15162784.log,
Nov. 27, 2015. cited by applicant .
Cate, Michael C., "Kinetics of the Ligand Exchange Reactions
Between Bidentate Ligands and Triethylenetetramine Nickelate (II)
and Synthesis of Boron (III) Subphthalocyanines with Various Boron
Substitutions," Eastern Michigan University, Apr. 1, 2007, Paper
43, pp. 1-88. cited by applicant .
Claessens, Christian G., et al., "Subphthalocyanines,
Subporphyrazines, and Subporphyrins: Singular Nonplanar Aromatic
Systems," American Chemical Society--Chemical Reviews, vol. 114,
No. 4, Feb. 26, 2014, pp. 2192-2277. cited by applicant .
Lin, Chi-Feng, et al., "Chloroboron subphthalocyanine/C60 planar
heterojunction organic solar cell with N,
N-dicarbazolyl-3,5-benzene blocking layer," Solar Energy Materials
& Solar Cells, Elsevier Science Publisher, Amsterdam, NL, vol.
122, Jan. 3, 2014, pp. 264-270. cited by applicant .
Lessard, Beno t H., "Bis(tri-n-hexylsilyl oxide) Silicon
Phthalocyanine: A Unique Additive in Ternary Bulk Heterojonction
Organic Photovoltaic Devices," American Chemical Society--Applied
Materials & Interfaces, vol. 6, Aug. 22, 2014, pp. 15040-15051.
cited by applicant .
European Search Report mailed on Dec. 8, 2015. cited by
applicant.
|
Primary Examiner: Diallo; Mamadou
Attorney, Agent or Firm: Harness, Dickey & Pierce,
P.L.C.
Claims
What is claimed is:
1. An organic photoelectronic device comprising: a first electrode
and a second electrode facing each other, and an active layer
between the first electrode and the second electrode, wherein the
active layer includes a first compound represented by the following
Chemical Formula 1: ##STR00037## wherein R.sup.1 to R.sup.12 are
independently hydrogen or a monovalent organic group, R.sup.1 to
R.sup.12 are independently present or form a ring, L.sup.1 to
L.sup.3 are independently a single bond or a divalent organic
group, and R.sup.13 to R.sup.15 are independently a substituted or
unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted
C6 to C30 aryl group, a substituted or unsubstituted C3 to C30
heterocyclic group, a substituted or unsubstituted C1 to C30 alkoxy
group, a substituted or unsubstituted amine group, a substituted or
unsubstituted C6 to C30 arylamine group, a substituted or
unsubstituted silyl group, or a combination thereof.
2. The organic photoelectronic device of claim 1, wherein R.sup.1
to R.sup.12 are independently hydrogen, a substituted or
unsubstituted C1 to C30 aliphatic hydrocarbon group, a substituted
or unsubstituted C6 to C30 aromatic hydrocarbon group, a
substituted or unsubstituted C1 to C30 aliphatic heterocyclic
group, a substituted or unsubstituted C2 to C30 aromatic
heterocyclic group, a substituted or unsubstituted C1 to C30 alkoxy
group, a substituted or unsubstituted C1 to C30 aryloxy group, a
thio group, an alkylthio group, an arylthio group, a cyano group, a
cyano-containing group, a halogen, a halogen-containing group, a
substituted or unsubstituted sulfonyl group, a substituted or
unsubstituted aminosulfonyl group, a substituted or unsubstituted
arylsulfonyl group, or a combination thereof, and L.sup.1 to
L.sup.3 are independently a single bond, a substituted or
unsubstituted C1 to C30 alkylene group, a substituted or
unsubstituted C6 to C30 arylene group, a divalent substituted or
unsubstituted C3 to C30 heterocyclic group, or a combination
thereof.
3. The organic photoelectronic device of claim 1, wherein the first
compound is configured to selectively absorb light in a green
wavelength region.
4. The organic photoelectronic device of claim 1, wherein the first
compound has a maximum absorption wavelength (.lamda..sub.max) of
about 500 nm to about 600 nm.
5. The organic photoelectronic device of claim 1, wherein the
active layer further comprises a second compound configured to
absorb light in a visible wavelength region.
6. The organic photoelectronic device of claim 5, wherein the
second compound comprises fullerene or a fullerene derivative.
7. The organic photoelectronic device of claim 5, wherein the
second compound comprises thiophene or a thiophene derivative.
8. The organic photoelectronic device of claim 1, wherein a light
absorption curve of the active layer has a full width at half
maximum (FWHM) of less than or equal to about 80 nm.
9. The organic photoelectronic device of claim 1, wherein at least
one of the first electrode and the second electrode are a
transparent electrode.
10. An image sensor comprising the organic photoelectronic device
of claim 1.
11. The image sensor of claim 10, comprising a semiconductor
substrate integrated with a plurality of first photo-sensing
devices configured to sense light in a blue wavelength region and a
plurality of second photo-sensing devices configured to sense light
in a red wavelength region, wherein the organic photoelectronic
device is on the semiconductor substrate and is configured to
selectively absorb light in a green wavelength region.
12. The image sensor of claim 11, wherein the first photo-sensing
devices and the second photo-sensing devices are stacked in a
substantially perpendicular direction to the semiconductor
substrate.
13. The image sensor of claim 11, further comprising: a color
filter layer between the semiconductor substrate and the organic
photoelectronic device, a blue filter configured to selectively
absorb light in a blue wavelength region, and a red filter
configured to selectively absorb light in a red wavelength
region.
14. The image sensor of claim 10, further comprising: a green
photoelectronic device of the organic photoelectronic device, a
blue photoelectronic device configured to selectively absorb light
in a blue wavelength region, and a red photoelectronic device
configured to selectively absorb light in a red wavelength region,
the blue photoelectronic device and the red photoelectronic device
being stacked on each other.
Description
RELATED APPLICATIONS
This application claims the benefit of priority from Korean Patent
Application No. 10-2014-0092001, filed in the Korean Intellectual
Property Office on Jul. 21, 2014, the entire contents of which are
incorporated herein by reference.
BACKGROUND
1. Field
Example embodiments relate to an organic photoelectronic device
and/or an image sensor.
2. Description of the Related Art
A photoelectronic device typically converts light into an
electrical signal using photoelectronic effects, and may include a
photodiode, a phototransistor, and the like, and it may be applied
to an image sensor, a solar cell, and the like.
An image sensor including a photodiode requires typically high
resolution and thus a small pixel. At present, a silicon photodiode
is widely used, but exhibits deteriorated sensitivity because of a
small absorption area due to the small pixels. Accordingly, an
organic material that is capable of replacing silicon has been
researched.
The organic material has a high extinction coefficient and
selectively absorbs light in a particular wavelength region
depending on a molecular structure, and thus may simultaneously
replace a photodiode and a color filter, and as a result improve
sensitivity and contribute to high integration.
SUMMARY
At least one example embodiment relates to an organic
photoelectronic device configured to increase wavelength
selectivity and decrease crosstalk between each pixel by improving
light absorption characteristics in a thin film state.
Another example embodiment relates to an image sensor including the
organic photoelectronic device.
According to one example embodiment, an organic photoelectronic
device includes a first electrode and a second electrode facing
each other, and an active layer interposed between the first
electrode and the second electrode, wherein the active layer
includes a first compound represented by the following Chemical
Formula 1.
##STR00002##
In the above Chemical Formula 1,
R.sup.1 to R.sup.12 are independently hydrogen or a monovalent
organic group,
R.sup.1 to R.sup.12 are independently present or form a ring,
and
L.sup.1 to L.sup.3 are independently a single bond or a divalent
organic group, R.sup.13 to R.sup.15 are independently a substituted
or unsubstituted C1 to C30 alkyl group, a substituted or
unsubstituted C6 to C30 aryl group, a substituted or unsubstituted
C3 to C30 heterocyclic group, a substituted or unsubstituted C1 to
C30 alkoxy group, a substituted or unsubstituted amine group, a
substituted or unsubstituted C6 to C30 arylamine group, a
substituted or unsubstituted silyl group, or a combination
thereof.
According to at least one example embodiment, R.sup.1 to R.sup.12
are independently hydrogen, a substituted or unsubstituted C1 to
C30 aliphatic hydrocarbon group, a substituted or unsubstituted C6
to C30 aromatic hydrocarbon group, a substituted or unsubstituted
C1 to C30 aliphatic heterocyclic group, a substituted or
unsubstituted C2 to C30 aromatic heterocyclic group, a substituted
or unsubstituted C1 to C30 alkoxy group, a substituted or
unsubstituted C1 to C30 aryloxy group, a thio group, an alkylthio
group, an arylthio group, a cyano group, a cyano-containing group,
a halogen, a halogen-containing group, a substituted or
unsubstituted sulfonyl group, a substituted or unsubstituted
aminosulfonyl group, a substituted or unsubstituted arylsulfonyl
group, or a combination thereof, and L.sup.1 to L.sup.3 are
independently a single bond, a substituted or unsubstituted C1 to
C30 alkylene group, a substituted or unsubstituted C6 to C30
arylene group, a divalent substituted or unsubstituted C3 to C30
heterocyclic group, or a combination thereof.
The first compound represented by Chemical Formula 1 may
selectively absorb light in a green wavelength region.
The first compound may have a maximum absorption wavelength
(.lamda..sub.max) of about 500 nm to about 600 nm.
The active layer may further include a second compound absorbing
light in a visible ray region.
The second compound may include fullerene or a fullerene
derivative.
The second compound may include thiophene or a thiophene
derivative.
The active layer may show a light absorption curve having a full
width at half maximum (FWHM) of less than or equal to about 80
nm.
The first electrode and the second electrode may respectively be a
transparent electrode.
According to another example embodiment, an image sensor including
the organic photoelectronic device is provided.
The image sensor may include a semiconductor substrate integrated
with a plurality of first photo-sensing devices sensing light in a
blue wavelength region and a plurality of second photo-sensing
devices sensing light in a red wavelength region, and the organic
photoelectronic device positioned on the semiconductor substrate
and selectively absorbing light in a green wavelength region.
The first photo-sensing device and the second photo-sensing device
may be stacked in a vertical direction on the semiconductor
substrate.
The image sensor may further include a color filter layer
positioned between the semiconductor substrate and the organic
photoelectronic device, and including a blue filter selectively
absorbing light in a blue wavelength region, and a red filter
selectively absorbing light in a red wavelength region.
The image sensor may include a green photoelectronic device of the
organic photoelectronic device, a blue photoelectronic device
selectively absorbing light in a blue wavelength region, and a red
photoelectronic device selectively absorbing light in a red
wavelength region and that are stacked.
According to another example embodiment, the compound represented
by the above Chemical Formula 1 is provided.
The compound represented by the above Chemical Formula 1 may be
configured to selectively absorb light in a green wavelength
region.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view showing an organic photoelectronic
device according to at least one example embodiment,
FIG. 2 is a cross-sectional view showing an organic photoelectronic
device according to another example embodiment,
FIG. 3 is a schematic top plan view showing an organic CMOS image
sensor according to at least one example embodiment,
FIG. 4 is a cross-sectional view showing the organic CMOS image
sensor of FIG. 3,
FIG. 5 is a schematic cross-sectional view showing an organic CMOS
image sensor according to another example embodiment,
FIG. 6 is a schematic top plan view showing an organic CMOS image
sensor according to another example embodiment,
FIG. 7 shows NMR data of the compound represented by Chemical
Formula 1a according to Synthesis Example 1, according to at least
one example embodiment,
FIG. 8 shows NMR data of the compound represented by Chemical
Formula 1b according to Synthesis Example 2, according to at least
one example embodiment,
FIG. 9 is a graph showing light absorption characteristics in a
solution state of the compounds according to Synthesis Example 1
and Comparative Synthesis Example 1,
FIG. 10 is a graph showing light absorption characteristics in a
thin film state of the compounds according to Synthesis Example 1
and Comparative Synthesis Example 1, and
FIG. 11 is a graph showing external quantum efficiency (EQE)
depending on a wavelength of the organic photoelectronic devices
according to Example 1 and Comparative Example 1.
DETAILED DESCRIPTION
It will be understood that when an element is referred to as being
"on," "connected" or "coupled" to another element, it can be
directly on, connected or coupled to the other element or
intervening elements may be present. In contrast, when an element
is referred to as being "directly on," "directly connected" or
"directly coupled" to another element, there are no intervening
elements present. As used herein the term "and/or" includes any and
all combinations of one or more of the associated listed items.
Further, it will be understood that when a layer is referred to as
being "under" another layer, it can be directly under or one or
more intervening layers may also be present. In addition, it will
also be understood that when a layer is referred to as being
"between" two layers, it can be the only layer between the two
layers, or one or more intervening layers may also be present.
It will be understood that, although the terms "first", "second",
etc. may be used herein to describe various elements, components,
regions, layers and/or sections, these elements, components,
regions, layers and/or sections should not be limited by these
terms. These terms are only used to distinguish one element,
component, region, layer or section from another element,
component, region, layer or section. Thus, a first element,
component, region, layer or section discussed below could be termed
a second element, component, region, layer or section without
departing from the teachings of example embodiments.
Spatially relative terms, such as "beneath," "below," "lower,"
"above," "upper" and the like, may be used herein for ease of
description to describe one element or feature's relationship to
another element(s) or feature(s) as illustrated in the figures. It
will be understood that the spatially relative terms are intended
to encompass different orientations of the device in use or
operation in addition to the orientation depicted in the figures.
For example, if the device in the figures is turned over, elements
described as "below" or "beneath" other elements or features would
then be oriented "above" the other elements or features. Thus, the
example term "below" can encompass both an orientation of above and
below. The device may be otherwise oriented (rotated 90 degrees or
at other orientations) and the spatially relative descriptors used
herein interpreted accordingly.
The terminology used herein is for the purpose of describing
particular embodiments only and is not intended to be limiting of
example embodiments. As used herein, the singular forms "a," "an"
and "the" are intended to include the plural forms as well, unless
the context clearly indicates otherwise. It will be further
understood that the terms "comprises" and/or "comprising," when
used in this specification, specify the presence of stated
features, integers, steps, operations, elements, and/or components,
but do not preclude the presence or addition of one or more other
features, integers, steps, operations, elements, components, and/or
groups thereof.
Example embodiments are described herein with reference to
cross-sectional illustrations that are schematic illustrations of
idealized embodiments (and intermediate structures) of example
embodiments. As such, variations from the shapes of the
illustrations as a result, for example, of manufacturing techniques
and/or tolerances, are to be expected. Thus, example embodiments
should not be construed as limited to the particular shapes of
regions illustrated herein but are to include deviations in shapes
that result, for example, from manufacturing. For example, an
implanted region illustrated as a rectangle will, typically, have
rounded or curved features and/or a gradient of implant
concentration at its edges rather than a binary change from
implanted to non-implanted region. Likewise, a buried region formed
by implantation may result in some implantation in the region
between the buried region and the surface through which the
implantation takes place. Thus, the regions illustrated in the
figures are schematic in nature and their shapes are not intended
to illustrate the actual shape of a region of a device and are not
intended to limit the scope of example embodiments.
Unless otherwise defined, all terms (including technical and
scientific terms) used herein have the same meaning as commonly
understood by one of ordinary skill in the art to which example
embodiments belong. It will be further understood that terms, such
as those defined in commonly-used dictionaries, should be
interpreted as having a meaning that is consistent with their
meaning in the context of the relevant art and will not be
interpreted in an idealized or overly formal sense unless expressly
so defined herein. As used herein, expressions such as "at least
one of," when preceding a list of elements, modify the entire list
of elements and do not modify the individual elements of the
list.
Example embodiments will hereinafter be described in detail, and
may be easily performed by those who have common knowledge in the
related art. However, this disclosure may be embodied in many
different forms and is not construed as limited to the example
embodiments set forth herein.
As used herein, when a definition is not otherwise provided, the
term "substituted" refers to one substituted with a substituent
such as a halogen (F, Br, Cl, or I), a hydroxy group, an alkoxy
group, a nitro group, a cyano group, an amino group, an azido
group, an amidino group, a hydrazino group, a hydrazono group, a
carbonyl group, a carbamyl group, a thiol group, an ester group, a
carboxyl group or a salt thereof, a sulfonic acid group or a salt
thereof, a phosphoric acid or a salt thereof, a C1 to C20 alkyl
group, a C2 to C20 alkenyl group, a C2 to C20 alkynyl group, a C6
to C30 aryl group, a C7 to C30 arylalkyl group, a C1 to C4 alkoxy
group, a C1 to C20 heteroalkyl group, a C3 to C20 heteroarylalkyl
group, a C3 to C30 cycloalkyl group, a C3 to C15 cycloalkenyl
group, a C6 to C15 cycloalkynyl group, a C2 to C20 heterocycloalkyl
group, and a combination thereof, instead of hydrogen of a
compound.
As used herein, when specific definition is not otherwise provided,
the term "hetero" refers to one including 1 to 3 heteroatoms such
as N, O, S, and P.
In the drawings, the thickness of layers, films, panels, regions,
etc., are exaggerated for clarity. Like reference numerals
designate like elements throughout the specification. It will be
understood that when an element such as a layer, film, region, or
substrate is referred to as being "on" another element, it can be
directly on the other element or intervening elements may also be
present. In contrast, when an element is referred to as being
"directly on" another element, there are no intervening elements
present.
In the drawings, parts having no relationship with the description
are omitted for clarity of the embodiments, and the same or similar
constituent elements are indicated by the same reference numerals
throughout the specification.
Hereinafter, a compound for an organic photoelectronic device
according to at least one example embodiment is described.
A compound for an organic photoelectronic device according to at
least one example embodiment is represented by the following
Chemical Formula 1.
##STR00003##
In the above Chemical Formula 1,
R.sup.1 to R.sup.12 are independently hydrogen or a monovalent
organic group,
R.sup.1 to R.sup.12 are independently present or form a ring,
L.sup.1 to L.sup.3 are independently a single bond or a divalent
organic group, and
R.sup.13 to R.sup.15 are independently a substituted or
unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted
C6 to C30 aryl group, a substituted or unsubstituted C3 to C30
heterocyclic group, a substituted or unsubstituted C1 to C30 alkoxy
group, a substituted or unsubstituted amine group, a substituted or
unsubstituted C6 to C30 arylamine group, a substituted or
unsubstituted silyl group, or a combination thereof.
For example, R.sup.1 to R.sup.12 may independently be hydrogen, a
substituted or unsubstituted C1 to C30 aliphatic hydrocarbon group,
a substituted or unsubstituted C6 to C30 aromatic hydrocarbon
group, a substituted or unsubstituted C1 to C30 aliphatic
heterocyclic group, a substituted or unsubstituted C2 to C30
aromatic heterocyclic group, a substituted or unsubstituted C1 to
C30 alkoxy group, a substituted or unsubstituted C1 to C30 aryloxy
group, a thio group, an alkylthio group, an arylthio group, a cyano
group, a cyano-containing group, a halogen atom, a
halogen-containing group, a substituted or unsubstituted sulfonyl
group, a substituted or unsubstituted aminosulfonyl group, a
substituted or unsubstituted arylsulfonyl group, or a combination
thereof, but are not limited thereto.
For example, L.sup.1 to L.sup.3 may independently be a single bond,
a substituted or unsubstituted C1 to C30 alkylene group, a
substituted or unsubstituted C6 to C30 arylene group, a divalent
substituted or unsubstituted C3 to C30 heterocyclic group, or a
combination thereof, but are not limited thereto.
The compound represented by the above Chemical Formula 1 may be
configured to selectively absorb light in a green wavelength
region, and may have, for example, a maximum absorption wavelength
(.lamda..sub.max) at about 500 nm to 600 nm.
Hereinafter, an organic photoelectronic device including the
compound is described referring to the drawings.
FIG. 1 is a cross-sectional view of an organic photoelectronic
device according to at least one example embodiment.
Referring to FIG. 1, an organic photoelectronic device 100
according to at least one example embodiment includes a first
electrode 10 and a second electrode 20, and an active layer 30
between the first electrode 10 and the second electrode 20.
One of the first electrode 10 and the second electrode 20 may be an
anode and the other may be a cathode. At least one of the first
electrode 10 and the second electrode 20 may be a
light-transmitting electrode, and the light-transmitting electrode
may include, for example, a transparent conductor such as indium
tin oxide (ITO) or indium zinc oxide (IZO), or a metal thin layer
of a thin monolayer or multilayer. When one of the first electrode
10 and the second electrode 20 is a non-light-transmitting
electrode, the first electrode 10 and the second electrode 20 may
include, for example, an opaque conductor such as aluminum
(Al).
For example, the first electrode 10 and the second electrode 20 may
be light-transmitting electrodes.
The active layer 30 may include a p-type semiconductor material and
an n-type semiconductor material to form a pn junction, and may
absorb external light to generate excitons and then may separate
the generated excitons into holes and electrons.
The example active layer 30 includes a first compound represented
by the following Chemical Formula 1.
##STR00004##
In the above Chemical Formula 1,
R.sup.1 to R.sup.12 are independently hydrogen or a monovalent
organic group,
R.sup.1 to R.sup.12 are independently present or form a ring,
L.sup.1 to L.sup.3 are independently a single bond or a divalent
organic group, and
R.sup.13 to R.sup.15 are independently a substituted or
unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted
C6 to C30 aryl group, a substituted or unsubstituted C3 to C30
heterocyclic group, a substituted or unsubstituted C1 to C30 alkoxy
group, a substituted or unsubstituted amine group, a substituted or
unsubstituted C6 to C30 arylamine group, a substituted or
unsubstituted silyl group, or a combination thereof.
For example, R.sup.1 to R.sup.12 may independently be hydrogen, a
substituted or unsubstituted C1 to C30 aliphatic hydrocarbon group,
a substituted or unsubstituted C6 to C30 aromatic hydrocarbon
group, a substituted or unsubstituted C1 to C30 aliphatic
heterocyclic group, a substituted or unsubstituted C2 to C30
aromatic heterocyclic group, a substituted or unsubstituted C1 to
C30 alkoxy group, a substituted or unsubstituted C1 to C30 aryloxy
group, a thio group, an alkylthio group, an arylthio group, a cyano
group, a cyano-containing group, a halogen atom, a
halogen-containing group, a substituted or unsubstituted sulfonyl
group, a substituted or unsubstituted aminosulfonyl group, a
substituted or unsubstituted arylsulfonyl group, or a combination
thereof, but are not limited thereto.
For example, L.sup.1 to L.sup.3 may independently be a single bond,
a substituted or unsubstituted C1 to C30 alkylene group, a
substituted or unsubstituted C6 to C30 arylene group, a divalent
substituted or unsubstituted C3 to C30 heterocyclic group, or a
combination thereof, but are not limited thereto.
The first compound may selectively absorb light in a green
wavelength region. The first compound may have a maximum absorption
wavelength (.lamda..sub.max) at about 500 nm to about 600 nm and an
energy bandgap of about 2.0 to about 2.5 eV.
The first compound has an axis substitution group having a planar
backbone consisting of boron (B), nitrogen (N) and carbon (C), and
a B--O--Si bond spread substantially vertically to the planar
backbone. This structure of the first compound may decrease and/or
prevent aggregation among molecules and improve film quality in a
thin film state. Accordingly, light absorption characteristics of
the first compound in a solution state may be prevented from being
largely changed from those in the thin film state, and thus from
being deteriorated.
For example, the active layer 30 may show a light absorption curve
having a full width at half maximum (FWHM) of less than or equal to
about 80 nm, for example of about 30 nm to about 80 nm, or for
example of about 30 nm to about 65 nm. Herein, the FWHM is a width
of a wavelength corresponding to a half of a maximum absorption
point. As used herein, when specific definition is not otherwise
provided, it may be defined by absorbance measured by UV-Vis
spectroscopy. A smaller FWHM indicates selective absorption of
light in a narrow wavelength region and high wavelength
selectivity. Accordingly, a compound having a FWHM within the range
may have high selectivity for a green wavelength region.
In the above Chemical Formula 1, the R.sup.1 to R.sup.15 and
L.sup.1 to L.sup.3 may include combinations of the above groups,
and may include, for example, groups listed in the following Table
1, but are not limited thereto.
TABLE-US-00001 TABLE 1 *--L.sup.1--R.sup.13 *--L.sup.2--R.sup.14
*--L.sup.3--R.sup.15 1 phenyl phenyl phenyl 2 methyl methyl methyl
3 ethyl ethyl ethyl 4 t-butyl t-butyl t-butyl 5 hexyl hexyl hexyl 6
methyl methyl methyl 7 ##STR00005## ##STR00006## ##STR00007## 8
##STR00008## ##STR00009## ##STR00010## 9 ##STR00011## ##STR00012##
##STR00013## 10 methyl methyl ##STR00014## 11 ##STR00015##
##STR00016## ##STR00017## 12 ##STR00018## ##STR00019## ##STR00020##
13 ##STR00021## ##STR00022## ##STR00023## 14 ##STR00024##
##STR00025## ##STR00026## 15 ##STR00027## ##STR00028## ##STR00029##
16 isopropyl ethyl Ethyl 17 SiMe.sub.3 SiMe.sub.3 SiMe.sub.3 Me:
methyl
The first compound represented by Chemical Formula 1 discussed
above may include a p-type semiconductor compound or an n-type
semiconductor compound. When the first compound is a p-type
semiconductor compound, a second compound as an n-type
semiconductor compound may be further included, and when the first
compound is an n-type semiconductor compound, a second compound as
a p-type semiconductor compound may be further included.
The second compound may be a material that absorbs a part of or all
of the full visible ray region, for example about 380 nm to about
780 nm.
For example, the second compound may be fullerene such as C60 or a
fullerene derivative.
For example, the second compound may be thiophene or a thiophene
derivative.
The thiophene derivative may be, for example, represented by the
following Chemical Formula 2 or Chemical Formula 3, but is not
limited thereto.
##STR00030##
In the above Chemical Formula 2 or 3,
T.sup.1, T.sup.2, and T.sup.3 are an aromatic ring including a
substituted or unsubstituted thiophene moiety,
T.sup.1, T.sup.2, and T.sup.3 are independently present or are
bonded to each other,
X.sup.3 to X.sup.8 are independently hydrogen, a substituted or
unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted
C6 to C30 aryl group, a substituted or unsubstituted C3 to C30
heterocyclic group, a cyano group, or a combination thereof,
and
EWG.sup.1 and EWG.sup.2 are independently an electron withdrawing
group.
For example at least one of X.sup.3 to X.sup.8 may be an electron
withdrawing group.
For example at least one of X.sup.3 to X.sup.8 may be a cyano
group.
For example T.sup.1, T.sup.2, and T.sup.3 may be selected from
groups listed in the following Group 1.
[Group 1]
##STR00031##
In the Group 1,
R.sup.16 to R.sup.31 are independently hydrogen, a substituted or
unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted
C6 to C30 aryl group, a substituted or unsubstituted C3 to C30
heteroaryl group, or a combination thereof.
For example, the thiophene derivative may be one of compounds
represented by the following Chemical Formulae 2a to 2c, 3a, and
3b.
##STR00032##
Herein, R.sup.32 to R.sup.35 are independently hydrogen, a
substituted or unsubstituted C1 to C30 alkyl group, a substituted
or unsubstituted C6 to C30 aryl group, a substituted or
unsubstituted C3 to C30 heteroaryl group, or a combination thereof,
and
EWG.sup.1 and EWG.sup.2 are independently an electron withdrawing
group. Examples of the electron withdrawing group may be a cyano
group or a cyano-containing group.
The active layer 30 may be a single layer or a multilayer. The
active layer 30 may be, for example, an intrinsic layer (I layer),
a p-type layer/I layer, an I layer/n-type layer, a p-type layer/I
layer/n-type layer, a p-type layer/n-type layer, and the like.
The intrinsic layer (I layer) may include the p-type semiconductor
compound and the n-type semiconductor compound in a ratio of about
1:100 to about 100:1. The compounds may be included in a ratio
ranging from about 1:50 to about 50:1 within the range,
specifically, about 1:10 to about 10:1, and more specifically,
about 1:about 1. When the p-type and n-type semiconductors have a
composition ratio within the above ranges, an exciton may be
effectively produced and a pn junction may be effectively
formed.
The p-type layer may include the p-type semiconductor compound, and
the n-type layer may include the n-type semiconductor compound.
The active layer 30 may have a thickness of about 1 nm to about 500
nm, and specifically, about 5 nm to about 300 nm. When the active
layer 30 has a thickness within the above ranges, the active layer
may effectively absorb light, effectively separate holes from
electrons, and deliver them, thereby effectively improving
photoelectric conversion efficiency.
In the organic photoelectronic device 100, when light enters from
the first electrode 10 and/or second electrode 20, and when the
active layer 30 absorbs light having a desired, or alternatively
predetermined wavelength region, excitons may be produced from the
inside. The excitons are separated into holes and electrons in the
active layer 30, and the separated holes are transported to an
anode that is one of the first electrode 10 and second electrode 20
and the separated electrons are transported to the cathode that is
the other of and the first electrode 10 and second electrode 20 so
as to flow a current in the organic photoelectronic device.
Hereinafter, an organic photoelectronic device according to another
example embodiment is described.
FIG. 2 is a cross-sectional view showing an organic photoelectronic
device according to another example embodiment.
Referring to FIG. 2, an organic photoelectronic device 200
according to the example embodiment includes a first electrode 10
and a second electrode 20 facing each other, and an active layer 30
between the first electrode 10 and the second electrode 20,
similarly to the above example embodiment.
However, the organic photoelectronic device 200 according to the
example embodiment further includes charge auxiliary layers 40 and
50 between the first electrode 10 and the active layer 30, and the
second electrode 20 and the active layer 30, unlike the above
example embodiment. The charge auxiliary layers 40 and 50 may
facilitate the transfer of holes and electrons separated from the
active layer 30, so as to increase efficiency.
The charge auxiliary layers 40 and 50 may be at least one of a hole
injection layer (HIL) for facilitating hole injection, a hole
transport layer (HTL) for facilitating hole transport, an electron
blocking layer (EBL) for preventing electron transport, an electron
injection layer (EIL) for facilitating electron injection, an
electron transport layer (ETL) for facilitating electron transport,
and a hole blocking layer (HBL) for preventing hole transport.
The charge auxiliary layers 40 and 50 may include, for example, an
organic material, an inorganic material, or an organic/inorganic
material. The organic material may be an organic compound having
hole or electron characteristics, and the inorganic material may
be, for example, a metal oxide such as molybdenum oxide, tungsten
oxide, nickel oxide, and the like.
The hole transport layer (HTL) may include one of, for example,
poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)
(PEDOT:PSS), polyarylamine, poly(N-vinylcarbazole), polyaniline,
polypyrrole, N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine (TPD),
4-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl (.alpha.-NPD),
m-MTDATA, 4,4',4''-tris(N-carbazolyl)-triphenylamine (TCTA), and a
combination thereof, but is not limited thereto.
The electron blocking layer (EBL) may include one of, for example,
poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)
(PEDOT:PSS), polyarylamine, poly(N-vinylcarbazole), polyaniline,
polypyrrole, N,N,N',N'-tetrakis(4-methoxyphenyl)-benzidine (TPD),
4-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl (.alpha.-NPD),
m-MTDATA, 4,4',4''-tris(N-carbazolyl)-triphenylamine (TCTA), and a
combination thereof, but is not limited thereto.
The electron transport layer (ETL) may include one of, for example,
1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA),
bathocuproine (BCP), LiF, Alq.sub.3, Gaq.sub.3, Inq.sub.3,
Znq.sub.2, Zn(BTZ).sub.2, BeBq.sub.2, and a combination thereof,
but is not limited thereto.
The hole blocking layer (HBL) may include one of, for example,
1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA),
bathocuproine (BCP), LiF, Alq.sub.3, Gaq.sub.3, Inq.sub.3,
Znq.sub.2, Zn(BTZ).sub.2, BeBq.sub.2, and a combination thereof,
but is not limited thereto.
Either one of the charge auxiliary layers 40 and 50 may be omitted,
according to at least one example embodiment.
The organic photoelectronic device may be applied to various
fields, for example a solar cell, an image sensor, a
photo-detector, a photo-sensor, and an organic light emitting diode
(OLED), but is not limited thereto.
Hereinafter, an example of an image sensor including the organic
photoelectronic device is described referring to drawings. As an
example of an image sensor, an organic CMOS image sensor is
described.
FIG. 3 is a schematic top plan view of an organic CMOS image sensor
according to at least one example embodiment, and FIG. 4 is a
cross-sectional view of the organic CMOS image sensor of FIG.
3.
Referring to FIGS. 3 and 4, an organic CMOS image sensor 300
according to at least one example embodiment includes a
semiconductor substrate 110 integrated with photo-sensing devices
50B and 50R, a transmission transistor (not shown), a charge
storage 55, a lower insulation layer 60, a color filter layer 70,
an upper insulation layer 80, and an organic photoelectronic device
100.
The semiconductor substrate 110 may include a silicon substrate,
and may be integrated with the photo-sensing device 50, the
transmission transistor (not shown), and the charge storage 55. The
photo-sensing devices 50R and 50B may include photodiodes.
The photo-sensing devices 50B and 50R, the transmission transistor,
and/or the charge storage 55 may be integrated in each pixel or in
one of the pixels, and as shown in the drawing, the photo-sensing
devices 50B and 50R may be included in a blue pixel and a red
pixel, and the charge storage 55 may be included in a green
pixel.
The photo-sensing devices 50B and 50R sense light, the information
sensed by the photo-sensing devices may be transferred by the
transmission transistor, the charge storage 55 is electrically
connected with the organic photoelectronic device 100, and the
information of the charge storage 55 may be transferred by the
transmission transistor.
In drawings, the photo-sensing devices 50B and 50R are, for
example, arranged in parallel without limitation, and the blue
photo-sensing device 50B and the red photo-sensing device 50R may
be stacked in a vertical direction.
A metal wire (not shown) and a pad (not shown) may be formed on the
semiconductor substrate 110. In order to decrease signal delay, the
metal wire and pad may be made of or include a metal having low
resistivity, for example, aluminum (Al), copper (Cu), silver (Ag),
and alloys thereof, but are not limited thereto. Further, the metal
wire and pad are not limited to the structure, and the metal wire
and pad may be positioned under the photo-sensing devices 50B and
50R.
The lower insulation layer 60 is formed on the metal wire and the
pad. The lower insulation layer 60 may be made of or include an
inorganic insulating material such as a silicon oxide and/or a
silicon nitride, or a low dielectric constant (low K) material such
as SiC, SiCOH, SiCO, and SiOF. The lower insulation layer 60 has a
trench exposing the charge storage 55. The trench may be filled
with fillers.
A color filter 70 is formed on the lower insulation layer 60. The
color filter 70 includes a blue filter 70B formed in the blue pixel
and a red filter 70R filled in the red pixel. In the example
embodiment, a green filter is not included, but a green filter may
be further included.
The color filter layer 70 may be omitted. For example, when the
blue photo-sensing device 50B and the red photo-sensing device 50R
are stacked in a vertical direction, the blue photo-sensing device
50B and the red photo-sensing device 50R may selectively absorb
light in each wavelength region depending on their stack depth, and
the color filter layer 70 may not be equipped.
The upper insulation layer 80 may be formed on the color filter 70.
The upper insulation layer 80 eliminates a step caused by the color
filter layer 70 and smoothens the surface. The upper insulation
layer 80 and the lower insulation layer 60 may include a contact
hole (not shown) exposing a pad, and a through-hole 85 exposing the
charge storage 55 of the green pixel.
The organic photoelectronic device 100 is formed on the upper
insulation layer 80. The organic photoelectronic device 100
includes the first electrode 10, the active layer 30, and the
second electrode 120 as described above.
The first electrode 10 and the second electrode 20 may be
transparent electrodes, and the active layer 30 is the same as
described above. The active layer 30 selectively absorbs light in a
green wavelength region and replaces a color filter of a green
pixel.
When light enters from the second electrode 20, the light in a
green wavelength region may be mainly absorbed in the active layer
30 and photoelectrically converted, while the light in the rest of
the wavelength regions passes through first electrode 10 and may be
sensed in the photo-sensing devices 50B and 50R.
As described above, the organic photoelectronic devices selectively
absorbing light in a green wavelength region are stacked, and a
size of an image sensor may be thereby decreased and a down-sized
image sensor may be realized.
As described above, the first compound represented by the above
Chemical Formula 1 as a p-type or n-type semiconductor compound is
prevented from being aggregated in a thin film state, and light
absorption characteristics depending on a wavelength may be
maintained. Accordingly, green wavelength selectivity may be
maintained, and crosstalk caused by unnecessary absorption light in
a wavelength region except green may be decreased while increasing
sensitivity.
In FIG. 4, the organic photoelectronic device 100 of FIG. 1 is
included, but it is not limited thereto, and thus the organic
photoelectronic device 200 of FIG. 2 may be applied in the same
manner.
FIG. 5 is a schematic cross-sectional view showing an organic CMOS
image sensor according to another example embodiment.
The organic CMOS image sensor 300 according to at least one example
embodiment includes a semiconductor substrate 110 integrated with
photo-sensing devices 50B and 50R, a transmission transistor (not
shown), a charge storage 55, an insulation layer 80, and an organic
photoelectronic device 100, similarly to the above example
embodiment illustrated in FIG. 4.
However, the organic CMOS image sensor 300 according to the example
embodiment includes the blue photo-sensing device 50B and the red
photo-sensing device 50R that are stacked, and does not include a
color filter layer 70, unlike the above example embodiment
illustrated in FIG. 4. The blue photo-sensing device 50B and the
red photo-sensing device 50R are electrically connected with the
charge storage (not shown), and the information of the charge
storage 55 may be transferred by the transmission transistor. The
blue photo-sensing device 50B and the red photo-sensing device 50R
may selectively absorb light in each wavelength region depending on
a stack depth.
As described above, the organic photoelectronic devices selectively
absorbing light in a green wavelength region are stacked and the
red photo-sensing device and the blue photo-sensing device are
stacked, and thereby a size of an image sensor may be decreased and
a down-sized image sensor may be realized. As described above, the
organic photoelectronic device 100 has improved green wavelength
selectivity, and crosstalk caused by unnecessary absorption light
in a wavelength region except green may be decreased while
increasing sensitivity.
In FIG. 5, the organic photoelectronic device 100 of FIG. 1 is
included, but it is not limited thereto, and thus the organic
photoelectronic device 200 of FIG. 2 may be applied in the same
manner.
FIG. 6 is a schematic top plan view of an organic CMOS image sensor
according to another example embodiment.
The organic CMOS image sensor according to the example embodiment
includes a green photoelectronic device G selectively absorbing
light in a green wavelength region, a blue photoelectronic device B
selectively absorbing light in a blue wavelength region, and a red
photoelectronic device R selectively absorbing light in a green
wavelength region and that are stacked.
In the drawing, the red photoelectronic device R, the green
photoelectronic device G, and the blue photoelectronic device B are
sequentially stacked, but the stack order may be changed without
limitation.
The green photoelectronic device may be the above organic
photoelectronic device 100, the blue photoelectronic device may
include electrodes facing each other with an active layer
therebetween and including an organic material selectively
absorbing light in a blue wavelength region, and the red
photoelectronic device may include electrodes facing each other
with an active layer therebetween and including an organic material
selectively absorbing light in a red wavelength region.
As described above, the organic photoelectronic device selectively
absorbing light in a red wavelength region, the organic
photoelectronic device selectively absorbing light in a green
wavelength region, and the organic photoelectronic device
selectively absorbing light in a blue wavelength region are
stacked, and thereby a size of an image sensor may be decreased and
a down-sized image sensor may be realized.
In FIG. 6, the organic photoelectronic device 100 of FIG. 1 is
included, but it is not limited thereto, and thus the organic
photoelectronic device 200 of FIG. 2 may be applied in the same
manner.
The image sensor may be applied to, or used in, various electronic
devices, for example a mobile phone, a digital camera, and the
like, but is not limited thereto.
Hereinafter, the example embodiments are illustrated in more detail
with reference to examples. However, the example embodiments are
not limited thereto.
SYNTHESIS EXAMPLES
Synthesis Example 1
##STR00033##
20.0 g of boron sub-phthalocyanine chloride (Sigma-Aldrich Co.,
Ltd.), 32.0 g of triphenylsilanol (Dong Kyung Co., Ltd.), and 14.8
g of silver trifluoromethanesulfonate (Dong Kyung Co., Ltd) are
heated and refluxed in 150 ml of dry toluene for 15 hours. Then,
200 ml of methylene chloride is added thereto, the mixture is
filtered, and the filtered solution is concentrated under a reduced
pressure and purified through silica gel column chromatography,
obtaining 13.5 g of a compound represented by the above Chemical
Formula 1a. The compound represented by the above Chemical Formula
1a is further purified through sublimation, and then applied to a
post-described organic photoelectronic device.
NMR data (BRUKER, 500 MHz) of the compound represented by the above
Chemical Formula 1a is provided in FIG. 7.
FIG. 7 shows NMR data of the compound represented by Chemical
Formula 1a according to Synthesis Example 1.
Synthesis Example 2
##STR00034##
4.6 g of the compound represented by the above Chemical Formula 1b
is obtained according to the same synthesis method as Synthesis
Example 1, except for using 23.8 g of potassium trimethyl siloxide
(Sigma-Aldrich Co., Ltd.) instead of the triphenylsilanol and
setting the reaction temperature at 50.degree. C. The compound
represented by the above Chemical Formula 1b is further purified
through sublimation, and then applied to a post-described organic
photoelectronic device.
NMR data (BRUKER, 500 MHz) of the compound represented by the above
Chemical Formula 1b is provided in FIG. 8.
FIG. 8 shows NMR data of the compound represented by Chemical
Formula 1b according to Synthesis Example 2.
Comparative Synthesis Example 1
A compound represented by the following Chemical Formula A (a
sublimated and refined product, LumTec, LLC) is prepared.
##STR00035##
Comparative Synthesis Example 2
A compound represented by the following Chemical Formula B is
prepared in a method described in Angewandte Chemie, International
Edition, Volume 50 Issue 15, pages 3506-3509.
##STR00036## Evaluation I Evaluation 1: Light Absorption
Characteristics
Light absorption characteristics of the compounds according to
Synthesis Examples 1 and 2 and Comparative Synthesis Examples 1 and
2 are evaluated depending on a wavelength.
The light absorption characteristics are evaluated in both solution
and thin film states of the compounds.
The light absorption characteristics in a solution state are
evaluated by dissolving each compound according to Synthesis
Examples 1 and 2 and Comparative Synthesis Examples 1 and 2 in a
concentration of 1.0.times.10.sup.-5 mol/L in toluene.
The light absorption characteristics in a thin film state are
evaluated by thermally evaporating each compound according to
Synthesis Examples 1 and 2 and Comparative Synthesis Examples 1 and
2 at a speed of 0.5-1.0 .ANG./s under high vacuum (<10.sup.-7
Torr) to respectively form 70 nm-thick thin films and radiating
ultraviolet (UV)-visible rays (UV-Vis) on the thin films with a
Cary 5000 UV spectroscope (Varian Inc.).
The results are provided in FIGS. 9 and 10 and Table 2.
FIG. 9 is a graph showing light absorption characteristics in a
solution state of the compounds according to Synthesis Example 1
and Comparative Synthesis Example 1, and FIG. 10 is a graph showing
light absorption characteristics in a thin film state of the
compounds according to Synthesis Example 1 and Comparative
Synthesis Example 1.
TABLE-US-00002 TABLE 2 .lamda..sub.max (nm) FWHM (nm) Energy level
solu- thin solu- thin HOMO LUMO tion film tion film (eV) (eV)
Synthesis Example 1 562 575 29 46 5.6 3.5 Synthesis Example 2 561
575 29 63 5.5 3.4 Comparative 565 587 23 81 5.6 3.6 Synthesis
Example 1 Comparative 562 582 29 83 5.5 3.4 Synthesis Example 2
Referring to FIG. 9 and Table 2, the compounds according to
Synthesis Examples 1 and 2 show similar or same light absorption
characteristics to those of the compounds according to Comparative
Synthesis Examples 1 and 2 in a solution state.
On the contrary, referring to FIG. 10 and Table 2, the compounds
according to Synthesis Examples 1 and 2 show a narrower FWHM and
higher green wavelength selectivity than the compounds according to
Comparative Synthesis Examples 1 and 2 in a thin film state.
Specifically, the compounds according to Comparative Synthesis
Examples 1 and 2 have a light absorption curve that is widened
toward a long wavelength, absorb light in a red wavelength region
ranging from about 600 nm to 650 nm, and respectively have a full
width at half maximum (FWHM) of about 81 nm and 83 nm, while the
compound according to Synthesis Example 1 maintains light
absorption characteristics in a green wavelength region and a
relatively narrow FWHM of about 46 nm, and the compound according
to Synthesis Example 2 maintains light absorption characteristics
in a green wavelength region and has a relatively narrow full width
at half maximum (FWHM) of about 63 nm. Accordingly, the compounds
according to Synthesis Examples 1 and 2 show a higher green
wavelength selectivity state in a thin film than the compounds
according to Comparative Synthesis Examples 1 and 2.
Manufacture of Organic Photoelectronic Device
Example 1
A substantially 100 nm-thick anode is formed by sputtering ITO on a
glass substrate, and then a substantially 10 nm-thick charge
auxiliary layer is formed thereon by depositing a molybdenum oxide
(MoO.sub.x, 0<x.ltoreq.3). Subsequently, a substantially 85
nm-thick active layer is formed on the molybdenum oxide thin film
by codepositing the compound (a p-type semiconductor compound)
according to Synthesis Example 1 and C60 (an n-type semiconductor
compound) in a thickness ratio of 1:1. Subsequently, a
substantially 80 nm-thick cathode is formed on the active layer by
sputtering ITO, manufacturing an organic photoelectronic
device.
Example 2
An organic photoelectronic device is manufactured according to the
same method as Example 1, except for using the compound according
to Synthesis Example 2 instead of the compound according to
Synthesis Example 1.
Comparative Example 1
An organic photoelectronic device is manufactured according to the
same method as Example 1, except for using the compound according
to Comparative Synthesis Example 1 instead of the compound
according to Synthesis Example 1.
Evaluation II
External quantum efficiency (EQE) of the organic photoelectronic
devices according to Examples 1 and 2 and Comparative Example 1
depending on a wavelength are evaluated.
The external quantum efficiency is measured by using an IPCE
measurement system (McScience Co., Ltd., Korea). First of all, the
IPCE measurement system is calibrated by using a Si photodiode
(Hamamatsu Photonics K.K., Japan) and mounted on the organic
photoelectronic devices according to Examples 1 and 2 and
Comparative Example 1, and their external quantum efficiency is
measured at a wavelength ranging from about 350 to 750 nm.
The results are provided in Table 3. Table 3 provides external
quantum efficiency (EQE) at a maximum absorption wavelength when a
voltage of -3 V is applied.
TABLE-US-00003 TABLE 3 EQE (%) Example 1 60 Example 2 65
Comparative Example 1 52
Referring to Table 3, the organic photoelectronic devices according
to Examples 1 and 2 show improved external quantum efficiency
compared with the organic photoelectronic device according to
Comparative Example 1.
Evaluation III
The external quantum efficiency of the organic photoelectronic
devices according to Example 1 and Comparative Example 1 measured
in Evaluation II is normalized. Subsequently, in the normalized
external quantum efficiency graph depending on a wavelength, the
width of a wavelength corresponding to a half of maximum external
quantum efficiency, that is, a full width at half maximum (FWHM),
of the external quantum efficiency is evaluated.
The results are shown in FIG. 11 and Table 4.
TABLE-US-00004 TABLE 4 FWHM (nm) (normalized EQE) Example 1 85
Comparative Synthesis Example 1 120
FIG. 11 is a graph showing the external quantum efficiency (EQE) of
the organic photoelectronic devices according to Example 1 and
Comparative Example 1 depending on a wavelength.
Referring to FIG. 11 and Table 4, the organic photoelectronic
device according to Example 1 shows external quantum efficiency
(EQE) having a narrower full width at half maximum (FWHM) in a
wavelength region ranging from about 500 nm to about 600 nm than
the organic photoelectronic device according to Comparative Example
1. Accordingly, the organic photoelectronic device according to
Example 1 shows a higher wavelength selectivity regarding the green
wavelength region than the organic photoelectronic device according
to Comparative Example 1 in normalized external quantum
efficiency.
Evaluation IV
Crosstalk of an image sensor manufactured by respectively applying
the organic photoelectronic devices according to Example 1 and
Comparative Examples 1 and 2 is evaluated.
The following crosstalk evaluation is performed as follows.
Each compound according to Synthesis Example 1 and Comparative
Synthesis Examples 1 and 2 and C60 in a ratio of 1:1 are
respectively formed as a layer, and n and k are obtained by using
spectroscopic ellipsometry. The n and k values and photoelectric
conversion efficiency of a silicon photodiode and an organic
photoelectronic device are used to obtain spectrum sensitivity of
red, green, and blue elements having a structure shown in FIG. 4 by
using an FDTD (finite difference time domain). Herein, a wavelength
region is divided into three regions of 440-480 nm (blue), 520-560
nm (green), and 590-630 nm (red), and the sensitivities of each of
the three regions are compared relatively to each other. In other
words, when the integral of a sensitivity curve of a blue element
in the 440-480 nm is arbitrarily defined as 100, the integrals of
the sensitivity curves of the red and green elements in the 440-480
nm are evaluated with respect to the arbitrarily defined level of
100 for the blue element. This value is a crosstalk of the red and
green elements regarding the blue region in the 440-480 nm range.
The same process is performed regarding the 520-560 nm range and
the 590-630 nm range to obtain each crosstalk therein. Lastly, the
6 values are averaged to obtain all crosstalk.
The results are provided in Table 5.
TABLE-US-00005 TABLE 5 Comparative Example 1 Comparative Example 1
R device G device B device Example 2 R device G device B device
440-480 nm 8.05 35.94 100.00 8.05 37.00 100.00 520-560 nm 5.18
100.00 8.19 7.13 100.00 11.24 590-630 nm 100.00 143.84 12.84 100.00
50.96 12.86 Average 35.7 (%) 36.5 (%) 21.2(%) crosstalk
In Table 5, the crosstalk in each pixel indicates a ratio of
unnecessarily inflowing light other than the light of a particular
wavelength region into each pixel when light in the wavelength
regions of 590-630 nm, 520-560 nm, and 440-480 nm inflow 100% into
the red pixel (R), green pixel (G), and blue pixel (B), and the
average crosstalk may be defined as an average of a ratio of
unnecessarily inflowing light into the red pixel (R) other than
light of a red wavelength region, a ratio of unnecessarily
inflowing light into the green pixel (G) other than light of a
green wavelength region, and a ratio of unnecessarily inflowing
light into the blue pixel (B)) other than light of a blue
wavelength region.
Referring to Table 5, the organic photoelectronic device according
to Example 1 shows a largely decreased average crosstalk compared
with the organic photoelectronic devices according to Comparative
Examples 1 and 2.
While the above example embodiments has been described in
connection with what is presently considered to be practical
exemplary embodiments, it is to be understood that the example
embodiments are not limited to the disclosed embodiments, but, on
the contrary, is intended to cover various modifications and
equivalent arrangements included within the spirit and scope of the
appended claims.
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